"We look at the structure of the PDF and say 'there's a one here with an A and B below; that should be represented by a multi-level list', 'here's a bunch of lines and squares, that looks like a table'. Even things like page numbers.

"It says page one of five in the corner; if I add a bunch of text it will say page one of six."

Pratley: "PDF is where documents go to die. Once something is in PDF, it's like a roach motel for data.

The Portable Document Format was developed by Adobe back in 1991, but has been an open standard since 2008.

It's not the first time an Adobe product has faced criticism from a major player and it's unlikely to be the last, but it's still a withering comment about one of our most familiar document types.